Answer
$x=-\displaystyle \frac{3}{2}$ or $x=\displaystyle \frac{7}{3}$
Work Step by Step
We solve by factoring:
$6x(x-1)=21-x$
$6x^{2}-6x=21-x$
$6x^{2}-5x-21=0$
$(2x+3)(3x-7)=0$
$2x+3=0$ or $3x-7=0$
So we have: $x=-\displaystyle \frac{3}{2}$ or $x=\displaystyle \frac{7}{3}$